Magnetic device and power converter employing the same

ABSTRACT

A magnetic device and power converter employing the same. In one embodiment, the magnetic device includes a first L-core segment including a first leg and a second leg extending therefrom, and an opposing second L-core segment including a first leg and a second leg extending therefrom. The magnetic device also includes a winding formed around at least one of the first leg and the second leg of the first L-core segment or the second L-core segment.

TECHNICAL FIELD

The present invention is directed, in general, to power electronics and,more specifically, to a magnetic device and power converter employingthe same.

BACKGROUND

A switched-mode power converter (also referred to as a “power converter”or “regulator”) is a power supply or power processing circuit thatconverts an input voltage waveform into a specified output voltagewaveform. Magnetic devices such as transformers and inductors are oftenemployed in power converters to store and/or transfer electrical energythrough the power converter. Inasmuch as the magnetic devices tend toaccount for a fair amount of the board space of the power converter andtake up disproportional time of the manufacturing process, it isadvantageous to employ a compact magnetic device with flexible design.Therefore, what is needed in the art is a building block for a lesscomplex magnetic core amenable to compact magnetic devices.

SUMMARY OF THE INVENTION

Technical advantages are generally achieved, by advantageous embodimentsof the present invention, including a magnetic device and powerconverter employing the same. In one embodiment, the magnetic deviceincludes a first L-core segment including a first leg and a second legextending therefrom, and an opposing second L-core segment including afirst leg and a second leg extending therefrom. The magnetic device alsoincludes a winding formed around at least one of the first leg and thesecond leg of the first L-core segment or the second L-core segment.

The foregoing has outlined rather broadly the features and technicaladvantages of the present invention in order that the detaileddescription of the invention that follows may be better understood.Additional features and advantages of the invention will be describedhereinafter, which form the subject of the claims of the invention. Itshould be appreciated by those skilled in the art that the conceptionand specific embodiment disclosed may be readily utilized as a basis formodifying or designing other structures or processes for carrying outthe same purposes of the present invention. It should also be realizedby those skilled in the art that such equivalent constructions do notdepart from the spirit and scope of the invention as set forth in theappended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, reference isnow made to the following descriptions taken in conjunction with theaccompanying drawings, in which:

FIG. 1 illustrates a block diagram of an embodiment of a powerconverter;

FIGS. 2 and 3 illustrate schematic diagrams of exemplary power trains ofa power converter employing a boost regulator;

FIGS. 4 and 5 illustrate schematic diagrams of embodiments of portionsof power converters;

FIG. 6 illustrates a timing diagram demonstrating an operation of thepower converter of FIGS. 4 and 5;

FIGS. 7 and 8 illustrate schematic diagrams of alternative embodimentsof portions of power converters;

FIG. 9 illustrates a schematic diagram of an alternative embodiment of apower converter;

FIG. 10 illustrates a schematic diagram of an alternative embodiment ofa power converter;

FIG. 11 illustrates perspective view of an embodiment of a portion of amagnetic device;

FIG. 12 illustrates a side view of an embodiment of a portion of amagnetic device; and

FIGS. 13 to 49 illustrate views of embodiments of magnetic devices.

Corresponding numerals and symbols in the different figures generallyrefer to corresponding parts unless otherwise indicated, and may not beredescribed in the interest of brevity after the first instance. TheFIGUREs are drawn to illustrate the relevant aspects of exemplaryembodiments.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The making and using of the present exemplary embodiments are discussedin detail below. It should be appreciated, however, that the presentinvention provides many applicable inventive concepts that can beembodied in a wide variety of specific contexts. The specificembodiments discussed are merely illustrative of specific ways to makeand use the invention, and do not limit the scope of the invention.

The present invention will be described with respect to exemplaryembodiments in a specific context, namely, magnetic devices employing anL-shaped core, methods of forming the same and power convertersemploying the magnetic devices. While the principles of the presentinvention will be described in the environment of a power converter, anyapplication that may benefit from the magnetic devices as describedherein including a power amplifier or a motor controller is well withinthe broad scope of the present invention.

Referring initially to FIG. 1, illustrated is a block diagram of anembodiment of a power converter. The power converter is coupled to asource of electrical power such as an ac mains for providing an ac inputvoltage V_(in). The power converter includes a power train 105 that iscontrolled by a controller 110. The controller 110 generally measures anoperating characteristic of the power converter such as an outputvoltage V_(out) and controls a duty cycle (generally designated “D”) ofa switch therein in response to the measured operating characteristic toregulate the characteristic. The power converter may form a section of apower supply and provide power to another subsystem thereof, such as anisolating dc-to-dc converter coupled to an output thereof that providesa regulated voltage to a load. The power train 105 may employ aregulator (e.g., a boost or buck regulator) as described herein. Thepower train 105 of the power converter generally includes a plurality ofswitches coupled to reactive circuit elements to provide the powerconversion function.

Turning now to FIGS. 2 and 3, illustrated are schematic diagrams ofexemplary power trains of a power converter employing a boost regulator.Beginning with FIG. 2, illustrated is a power train 200 employing aboost regulator. The power converter receives an input voltage V_(in)(e.g., an unregulated ac input voltage) from a source of electricalpower such as an ac mains at an input thereof and provides a regulatedoutput voltage V_(out) at an output of the power converter. In keepingwith the principles of a boost topology, the output voltage V_(out) isgenerally higher than the input voltage V_(in) such that a switchingoperation thereof can regulate the output voltage V_(out). A main switchS₁ (e.g., an N-channel metal-oxide semiconductor “active” switch) of theboost regulator is enabled to conduct by a gate drive signal GD for aprimary interval D and couples the input voltage V_(in) through arectifier bridge 205 to a boost inductor L_(boost). During the primaryinterval D, a rectified input current or input current flows through theboost inductor L_(boost) to local circuit ground.

The duty cycle for the power train 200 depends in steady state, undercontinuous current in the boost inductor L_(boost), on the ratio of theinput and output voltages V_(in), V_(out), respectively, according tothe equation:

$D = {1 - {\frac{V_{i\; n}}{V_{{out}\;}}.}}$

During a complementary interval 1-D, the main switch S₁ is transitionedto a non-conducting state and an auxiliary switch (e.g., a diode D1)conducts. In an alternative circuit arrangement, the auxiliary switchmay include a second active switch that is controlled to conduct by acomplementary gate drive signal. The diode D1 provides a path tomaintain continuity of the input current i_(in) flowing through theboost inductor L_(boost). During the complementary interval 1-D, theinput current i_(in) flowing through the boost inductor L_(boost)decreases, and may become zero and remain zero for a period of timeresulting in a “discontinuous conduction mode” of operation.

During the complementary interval 1-D, the current flowing through theboost inductor L_(boost) flows through the diode D1 into an outputfilter capacitor C. In general, the duty cycle of the main switch S₁(and the complementary duty cycle of the diode D1) may be adjusted tomaintain a regulation of the output voltage V_(out) of the powerconverter. The conduction periods for the main and auxiliary switchesmay be substantially equal or varied to maintain a regulation of theoutput voltage V_(out) of the power converter. Those skilled in the artunderstand that conduction periods for the main and auxiliary switchesmay be separated by a small time interval by the use of “snubber”circuit elements (not shown) or by control circuit timing to avoid crossconduction current therebetween, and beneficially to reduce theswitching losses associated with the power converter. Circuit andcontrol techniques to avoid cross conduction currents between switchesare well understood in the art and will not be described further in theinterest of brevity.

Turning now to FIG. 3, illustrated is an exemplary power train 300 of apower converter employing first and second boost regulators coupled tofirst and second boost inductors L_(boost1), L_(boost2), respectively.The first boost regulator includes a first main switch S1 and a firstauxiliary switch (e.g., a first diode D1). The second boost regulatorincludes a second main switch S2 and a second auxiliary switch (e.g., asecond diode D2). The first and second main switches S1, S2 receivefirst and second gate drive signals GD_(S1), GD_(S2), respectively,generally controlled to operate roughly 180 degrees out of phase withrespect to each other. Out-of-phase operation of the boost regulatorsprovides an interleaving effect that doubles the ripple frequency andreduces the ripple magnitude for an ac input current delivered to arectifier bridge 305. The rectifier bridge 305 provides a rectifiedinput current or input current i_(in). A similar effect is achieved forthe current supplied to an output filter capacitor C. The reduction ofswitching ripple in the ac input current helps reduce filteringrequirements for an input filter (not shown) to reduce undesirablehigh-frequency components. Although substantial benefits can accrue fromthe interleaving effects between two boost regulators, the designchallenges previously described to implement efficient boost inductorsstill remain. Remaining circuit elements in FIG. 3 and in followingFIGUREs that are similar to those in FIG. 2 and other FIGUREs will notgenerally be described again in the interest of brevity.

Turning now to FIGS. 4 and 5, illustrated are schematic diagrams ofembodiments of portions of power converters. More specifically, FIG. 4illustrates a power train employing a boost topology with twointerleaved boost regulators (e.g., first and second boost regulators)and a coupled boost inductor L_(boost). It should be understood,however, that other topologies such as a buck topology with interleavedregulators (e.g., first and second regulators) and a coupled inductor asdescribed herein are well within the broad scope of the presentinvention. The coupled boost inductor L_(boost) includes a commonwinding N_(ic) (coupled between nodes 1 and 2), a first winding N_(sc1)(coupled between nodes 2 and 3), and a second winding N_(sc2) (coupledbetween nodes 2 and 4). The first and second windings N_(sc1), N_(sc2)are electrically and magnetically coupled to the common winding N_(ic).In an advantageous embodiment, the first and second windings N_(sc1),N_(sc2) have equal numbers of turns and will hereinafter be representedwith a reference symbol N_(S). Dots are illustrated in the FIGUREadjacent to the windings to indicate the sense of each winding (i.e.,the winding direction and the sense of the magnetically induced voltagetherein).

In an advantageous embodiment, the interleaved boost regulators arecontrolled to provide an input current with high-power factor. The firstboost regulator includes a first main switch (e.g., a field-effecttransistor) S₁ and a first auxiliary switch (e.g., a first diode D1),and is coupled to a portion of the coupled boost inductor L_(boost)including the common winding N_(ic) and the first winding N_(sc1). Thesecond boost regulator includes a second main switch (e.g., afield-effect transistor) S₂ and a second auxiliary switch (e.g., asecond diode D2), and is coupled to a portion of the coupled boostinductor L_(boost) including the common winding N_(ic) and the secondwinding N_(sc2). The output currents from the boost regulators of thepower train are interleaved and flow through the first and second diodesD1, D2 into an output filter capacitor C. Similarly, the rectified inputcurrent or input current i_(in) to the boost regulators are interleavedand flow through the common winding N_(ic). The first and second mainswitches S₁, S₂ are controlled by control signals GD_(S1), GD_(S2),respectively, to provide duty-cycle control for each of the twointerleaved boost regulators. Typically, the control signals GD_(S1),GD_(S2) are controlled 180 degrees out of phase with respect to eachother, and provide a common duty cycle (generally designated “D”) foreach boost regulator. It is also possible for the control signalsGD_(S1), GD_(S2) to be independently controlled to provide two distinctduty cycles to ensure that the inductor currents i₁, i₂ are equal. Aload, represented by current source CS, is coupled to output terminalsof the power converter and draws a current i_(o).

A common winding N_(ic) with selected turns can be formed around acommon leg (e.g., a center leg) of a magnetic core of the coupled boostinductor L_(boost). In an alternative embodiment, the common windingN_(ic) with selected turns may be formed around a common leg of amagnetic core that is not geometrically a center leg. Thus, the termcommon leg may include a leg of a magnetic core that may not begeometrically located as a center leg. (See, e.g., U.S. Pat. No.8,125,205, entitled “Power Converter Employing Regulators with a CoupledInductor,” issued on Feb. 28, 2012, to Chandrasekaran, et al., which isincorporated herein by reference.)

With respect to FIG. 5, illustrated is a schematic diagram of analternative embodiment of a power converter with a power train havingtwo interleaved boost regulators utilizing a couple boost inductorL_(boost). Again, other topologies such as a buck-boost topology withinterleaved regulators (e.g., first and second regulators) and a coupledinductor as described herein are well within the broad scope of thepresent invention. The couple boost inductor L_(boost) includes a commonwinding N_(ic) between nodes 1A and 1B, coupled to node 2 thereof in areturn leg of the boost regulator that is coupled to the source ofelectrical power for providing an input voltage V_(in). A first windingN_(sc1) of the couple boost inductor L_(boost) is coupled between nodes2 and 3, and a second winding N_(sc2) is coupled between node 2 and node4. The first and second windings N_(sc1), N_(cs2) are magneticallycoupled to the common winding N_(ic) and are electrically coupled to thecommon winding N_(ic). The operation of the power converter illustratedin FIGS. 4 and 5 is substantially similar. Remaining elements in FIG. 5with reference designations corresponding to those in FIG. 4 aresubstantially the same and will not be redescribed in the interest ofbrevity.

In a further alternative embodiment of the couple boost inductorL_(boost), the first and second windings N_(sc1), N_(sc2) can beelectrically coupled together external to the magnetic device forming aportion of the couple boost inductor L_(boost). In a further alternativeembodiment of the couple boost inductor L_(boost), the common windingN_(ic) can be separated into two winding parts, each part coupled in thepower converter as indicated in FIGS. 4 and 5 for the respectivewinding.

Turning now to FIG. 6, illustrated is a timing diagram demonstrating anoperation of the power converter of FIGS. 4 and 5. The period of aswitching cycle is represented by the variable T_(S). The periods whenthe first and second main switches S₁, S₂ are enabled to conduct arerepresented by the quantity D T_(s), which is assumed to be the sameinterval of time therefor. The first and second main switches S₁, S₂ areoperated 180 degrees out of phase by a delay 0.5·T_(S) as shown in FIG.6.

Turning now to FIGS. 7 and 8, illustrated are schematic diagrams ofalternative embodiments of portions of power converters. Morespecifically, FIG. 7 illustrates a power converter employing buckregulators with a coupled inductor. FIG. 8 illustrates a power converteremploying buck-boost regulators with a coupled inductor. While theoperation of the power converters of FIGS. 7 and 8 differs toaccommodate the buck and buck-boost operation, respectively, theprinciples of the present invention with respect to the interleavedregulators and coupled inductor are analogous to the principles asdescribed above and will not hereinafter be repeated.

Turning now to FIG. 9, illustrated is a schematic diagram of analternative embodiment of a power converter. The power converterincludes two interleaved half-bridge, isolated current double rectifiers(designated “CDR-I” and “CDR-II”). The power converter is operated byapplying an ac input voltage through a source of electrical powerthrough a bridge rectifier (not shown) to provide a dc input voltageV_(dc) to respective primary windings. The dc input voltage V_(dc) isconnected across a first series-connected pair of switches S₁₁, S₁₂, andacross a second series-connected pair of switches S₂₁, S₂₂. The firstseries-connected pair of switches S₁₁, S₁₂ are connected together at afirst node N₁, and the second series-connected pair of switches S₂₁, S₂₂are connected together at a second node N₂. The first and secondseries-connected pair of switches S₁₁, S₁₂, S₂₁, S₂₂ are preferablyfield-effect transistors, each having a parasitic diode connectedthereacross. The dc input voltage V_(dc) is also connected across a pairof capacitors C1, C2, which are connected together at a first commonnode N_(c1). The first and second series-connected pair of switches S₁₁,S₁₂, S₂₁, S₂₂ are operated with a controller 910 to generate a firstdrive voltage V_(p1) between the first node N₁ and the first common nodeN_(c1), and a second drive voltage V_(p2) between the second node N₂ andthe first common node N_(c1).

The first interleaved half-bridge, isolated current double rectifierCDR-I includes two series-connected primary windings PR₁₁, PR₁₂, whichare connected across the first node N₁ and the first common node N_(c1)and thus are driven with the first drive voltage V_(p1). A pair ofsecondary windings SC₁₁, SC₁₂ are connected together at an output nodeN_(o), and are magnetically coupled to the primary windings PR₁₁, PR₁₂,respectively. A pair of series-connected synchronous rectifier switchesSR₁₁, SR₁₂ are connected in parallel with secondary windings SC₁₁, SC₁₂,respectively, and connected together at a second common node N_(c2).Similarly, the second interleaved half-bridge, isolated current doublerectifier CDR-II includes two series-connected primary windings PR₂₁,PR₂₂, which are connected across the second node N₂ and the first commonnode N_(c1) and thus are driven with the second drive voltage V_(p2). Apair of secondary windings SC₂₁, SC₂₂ are connected together at anoutput node N_(o), and are magnetically coupled to the primary windingsPR₂₁, PR₂₂, respectively. A pair of series-connected synchronousrectifier switches SR₂₁, SR₂₂ are connected in parallel with secondarywindings SC₂₁, SC₂₂, respectively, and connected together at the secondcommon node N_(c2). The synchronous rectifier switches SR₁₁, SR₁₂, SR₂₁,SR₂₂ are preferably field-effect transistors, each having a parasiticdiode connected thereacross. Alternatively, the synchronous rectifierswitches SR₁₁, SR₁₂, SR₂₁, SR₂₂ can be replaced with diodes and orientedin a similar manner to the parasitic diodes. An output filter capacitorC3 is connected between the output node N_(o) and the second common nodeN_(c2), wherein an output voltage V_(o) is to be provided to a loadcoupled thereto.

The ac input voltages are generated in accordance with the symmetricmodulation scheme. In accordance therewith, the drive voltages appliedto respective current doubler rectifiers are phase-shifted with respectto each other by T_(s)/(2*N), wherein T_(s) is the drive voltages'switching period and N is the number of current doubler rectifiers. Forthe illustrated power converter with N=2, the controller 910 operatesthe switches S₁₁, S₁₂, S₂₁, S₂₂ such that the first and second drivevoltages V_(p1), V_(p2) are phase-shifted by one-fourth the switchingperiod T_(s), which ensures that the rectified output currents of thetwo current doubler rectifiers are interleaved. The controller 910 alsoprovides the signals needed to operate the synchronous rectifierswitches SR₁₁, SR₁₂, SR₂₁, SR₂₂. The controller 910 operates theaforementioned switches in accordance with the output voltage V_(o) ofthe power converter. (See, e.g., U.S. Pat. No. 7,046,523, entitled “CoreStructure and Interleaved DC-DC Converter Topology,” issued on May 16,2006, to Sun, et al. and U.S. Pat. No. 8,134,443, entitled “Extended EMatrix Integrated Magnetic (MIM) Core,” issued on Mar. 13, 2012, toChandrasekaran, et al., which are incorporated herein by reference.)

Turning now to FIG. 10, illustrated is a schematic diagram of analternative embodiment of a power converter. The power converterincludes a current doubler rectifier (“CDR”) and a controller. Thecurrent doubler rectifier employs a double-ended, half-bridge topologywhich is capable of applying positive, negative, and zero voltagesthereacross. The current doubler rectifier includes first and secondcapacitors C1, C2, and first and second switches S₁, S₂. The first andsecond capacitors C1, C2 and the first and second switches S₁, S₂receive a dc input voltage V_(in). The first and second capacitors C1,C2 may, for example, be electrolytic tantalum capacitors and the firstand second switches S₁, S₂ may be metal-oxide semiconductor field-effecttransistors.

The current doubler rectifier includes a magnetic device with a magneticcore MC, a primary winding (designated “N_(p)”) and a secondary winding(designated “N_(s)”). The current doubler rectifier also includes anoutput filter capacitor C_(out), and first and second rectifier diodesD₁, D₂. The magnetic core MC includes a center leg CL, a first outer legOL1 and a second outer leg OL2. The first and second outer legs OL1, OL2are disposed on opposite sides of the center leg CL. The primary windingN_(p) includes a first primary winding PR1 that is formed around thefirst outer leg OL1 and a second primary winding PR2 formed around thesecond outer leg OL2. The secondary winding N_(s) includes first, secondand third secondary winding SC1, SC2, SC3 formed around the first outerleg OL1, the second outer leg OL2 and the center leg CL, respectively.The duty cycle of the first and second switches S₁, S₂ is controlled soas to reduce a deviation of an output voltage V_(o) from a predeterminedsetpoint level.

In addition to controlling the duty cycle of the first and secondswitches S₁, S₂, a controller may also control the output rectifierswhen the first and second rectifier diodes D₁, D₂ are replaced withactive switches (e.g., synchronous rectifier switches). The controllerincludes an isolation circuit (e.g., a transformer) that provideselectrical isolation between the components on either side of themagnetic device.

In operation, the input voltage V_(in) is applied to the first andsecond capacitors C1, C2 and the first and second switches S₁, S₂. Thefirst and second switches S₁, S₂ are controlled by a drive controlcircuit of the controller in a complementary way. The first and secondswitches S₁, S₂ apply an ac voltage V_(ab) to the primary winding N_(p)leading to a first current i₁ through the first secondary winding SC1, asecond current i₂ through the second secondary winding SC2 and a thirdcurrent i₃ through the third secondary winding SC3 (where i₁+i₂=i₃). Thefirst and second currents i₁, i₂ are rectified by the first and secondrectifier diodes D₁, D₂, respectively. The third current i₃ charges theoutput filter capacitor C_(out), which then provides power to a loadcoupled to the output of the power converter. (See, e.g., U.S. Pat. No.6,549,436, entitled “Integrated Magnetic Converter Circuit and Methodwith Improved Filtering,” issued on Apr. 15, 2003, to Sun, which isincorporated herein by reference.)

Turning now to FIG. 11, illustrated is perspective view of an embodimentof a portion of a magnetic device. In particular, an L-core segment isillustrated having a first leg LEG1 and a second leg LEG2. The first legLEG1 has a length L1 and a thickness TH1 and the second leg LEG2 has alength L2 and a thickness TH2. In an illustrated embodiment, the lengthL1 of the first leg LEG1 is elongated (i.e., extended or longer) withrespect to the length L2 of the second leg LEG2 (e.g., L1≠L2) and thesecond leg LEG2 is substantially perpendicular to the first leg LEG1. Itshould be understood, however, that the first and second legs LEG1, LEG2may be substantially the same length (e.g., L1=L2) and the second legLEG2 may extend from the first leg LEG1 at different angles. While thefirst and second legs LEG1, LEG2 are illustrated having the samethickness (e.g., TH1=TH2), it is contemplated that the thickness of thelegs may be different (e.g., TH1≠TH2). The L-core segment provides aless complex magnetic core amenable to compact magnetic devices. TheL-core segment also provides a structure that allows windings to beformed thereabout without a bobbin. Additionally, the L-core segment canbe used as a building block for multiple magnetic core geometries andmagnetic device assemblies.

Turning now to FIG. 12, illustrated is a side view of an embodiment of aportion of a magnetic device. A magnetic core of the magnetic deviceincludes a first L-core segment LC1 and an opposing second L-coresegment LC2. The first L-core segment LC1 includes a first leg LEG1 anda second leg LEG2 extending therefrom. The second L-core segment LC2includes a first leg LEG1 and a second leg LEG2 extending therefrom. Anend surface ES of the second leg LEG2 of the first L-core segment LC1mates with (e.g., glued, adhesively secured or banded together) aportion of an internal surface IS of the first leg LEG1 of the secondL-core segment LC2. Also, an end surface ES of the second leg LEG2 ofthe second L-core segment LC2 mates with (e.g., glued, adhesivelysecured or banded together) a portion of an internal surface IS of thefirst leg LEG1 of the first L-core segment LC1. The first and secondL-core segments LC1, LC2 may be designed with the flexibility asdescribed above with respect to FIG. 11.

Turning now to FIGS. 13 to 16, illustrated are views of an embodiment ofa magnetic device. FIGS. 13 and 14 illustrate a schematic view and aside view, respectively, of the magnetic device having primary windingscoupled in series and secondary windings coupled in parallel around amagnetic core. FIGS. 15 and 16 illustrate partially assembledperspective views of the magnetic device. The magnetic core of themagnetic device includes a first L-core segment LC1 and an opposingsecond L-core segment LC2. The first L-core segment LC1 includes a firstleg LEG1 and a second leg LEG2 extending therefrom. The second L-coresegment LC2 includes a first leg LEG1 and a second leg LEG2 extendingtherefrom. The first and second L-core segments LC1, LC2 may be designedwith the flexibility as described above with respect to FIGS. 11 and 12.

The magnetic device includes a first primary winding PR1 coupled inseries with a second primary winding PR2 with first, second and thirdprimary terminals p₁, p₂, p₃ for connection to another circuit elementof a power converter or the like. An end of the first and second primarywindings PR1, PR2 are coupled together at the third primary terminal p₃.The first primary winding PR1 is formed around (e.g., wound around) thefirst leg LEG1 of the first L-core segment LC1 and the second primarywinding PR2 is formed around (e.g., wound around) the first leg LEG1 ofthe second L-core segment LC2.

The magnetic device includes a first secondary winding SC1 coupled inparallel with a second secondary winding SC2 with first and secondsecondary terminals s₁, s₂ for connection to another circuit element ofa power converter or the like. An end of the first and second secondarywindings SC1, SC2 are coupled together. The first secondary winding SC1is formed around (e.g., stamped and formed sheet of metal placed around)the first leg LEG1 of the first L-core segment LC1 and the secondsecondary winding SC2 is formed around (e.g., stamped and formed sheetof metal placed around) the first leg LEG1 of the second L-core segmentLC2. The first secondary winding SC1 is formed over the first primarywinding PR1 around the first leg LEG1 of the first L-core segment LC1,and the second secondary winding SC2 is formed over the second primarywinding PR2 around the first leg LEG1 of the second L-core segment LC2.

The primary windings PR1, PR2 may be dielectrically isolated fromrespective secondary windings SC1, SC2 by an insulating layer (e.g.,tape or bobbin, not shown). Additionally, the primary windings PR1, PR2and/or the secondary windings SC1, SC2 may be dielectrically isolatedfrom the respective first and second L-core segments LC1, LC2 by aninsulating layer (e.g., tape or bobbin, not shown). The magnetic devicemay also be encapsulated by a protective potting material such as epoxyindividually or in combination with other circuit elements as part of apower converter or the like.

Turning now to FIGS. 17 to 20, illustrated are views of an embodiment ofa magnetic device. FIGS. 17 and 18 illustrate a schematic view and aside view, respectively, of the magnetic device having primary windingscoupled in parallel and secondary windings coupled in parallel around amagnetic core. FIGS. 19 and 20 illustrate partially assembledperspective views of the magnetic device. The magnetic core of themagnetic device includes a first L-core segment LC1 and an opposingsecond L-core segment LC2. The first L-core segment LC1 includes a firstleg LEG1 and a second leg LEG2 extending therefrom. The second L-coresegment LC2 includes a first leg LEG1 and a second leg LEG2 extendingtherefrom. The first and second L-core segments LC1, LC2 may be designedwith the flexibility as described above with respect to FIGS. 11 and 12.

The magnetic device includes a first primary winding PR1 coupled inparallel with a second primary winding PR2 with first and second primaryterminals p₁, p₂ for connection to another circuit element of a powerconverter or the like. Ends of the first and second primary windingsPR1, PR2 are coupled together at the first and second primary terminalsp₁, p₂. The first primary winding PR1 is formed around (e.g., woundaround) the first leg LEG1 of the first L-core segment LC1 and thesecond primary winding PR2 is formed around (e.g., wound around) thefirst leg LEG1 of the second L-core segment LC2.

The magnetic device includes a first secondary winding SC1 coupled inparallel with a second secondary winding SC2 with first and secondsecondary terminals s₁, s₂ for connection to another circuit element ofa power converter or the like. An end of the first and second secondarywindings SC1, SC2 are coupled together. The first secondary winding SC1is formed around (e.g., stamped and formed sheet of metal placed around)the first leg LEG1 of the first L-core segment LC1 and the secondsecondary winding SC2 is formed around (e.g., stamped and formed sheetof metal placed around) the first leg LEG1 of the second L-core segmentLC2. The first secondary winding SC1 is formed over the first primarywinding PR1 around the first leg LEG1 of the first L-core segment LC1,and the second secondary winding SC2 is formed over the second primarywinding PR2 around the first leg LEG1 of the second L-core segment LC2.

The primary windings PR1, PR2 may be dielectrically isolated fromrespective secondary windings SC1, SC2 by an insulating layer (e.g.,tape or bobbin, not shown). Additionally, the primary windings PR1, PR2and/or the secondary windings SC1, SC2 may be dielectrically isolatedfrom the respective first and second L-core segments LC1, LC2 by aninsulating layer (e.g., tape or bobbin, not shown). The magnetic devicemay also be encapsulated by a protective potting material such as epoxyindividually or in combination with other circuit elements as part of apower converter or the like.

Thus, a magnetic device, a method of forming the same and a powerconverter have been introduced herein. In one embodiment, the magneticdevice includes a first L-core segment including a first leg and asecond leg extending therefrom. The magnetic device also includes anopposing second L-core segment including a first leg and a second legextending therefrom. The magnetic device further includes a windingformed around at least one of the first leg and the second leg of thefirst L-core segment or the second L-core segment. In one embodiment,the second leg of the first L-core segment is substantiallyperpendicular to the first leg of the first L-core segment and thesecond leg of the second L-core segment is substantially perpendicularto the first leg of the second L-core segment. Additionally, a length ofthe first leg of the first L-core segment is elongated with respect to alength of the second leg of the first L-core segment and a length of thefirst leg of the second L-core segment is elongated with respect to alength of the second leg of the second L-core segment. Additionally, athickness of the first leg and the second leg of the first L-coresegment is substantially equal and a thickness of the first leg and thesecond leg of the second L-core segment is substantially equal.

In one embodiment, a primary winding is formed around the first leg ofthe first L-core segment and a secondary winding is formed around one ofthe first leg of the first L-core segment and the first leg of thesecond L-core segment. In yet another embodiment, a first primarywinding is formed around the first leg of the first L-core segment inseries with a second primary winding formed around the first leg of thesecond L-core segment. Alternatively, a first primary winding is formedaround the first leg of the first L-core segment in parallel with asecond primary winding formed around the first leg of the second L-coresegment. In a related embodiment, a first secondary winding is formedaround the first leg of the first L-core segment in parallel with asecond secondary winding formed around the first leg of the secondL-core segment. Additionally, a first secondary winding is formed over afirst primary winding around the first leg of the first L-core segment,and a second secondary winding is formed over a second primary windingaround the first leg of the second L-core segment. The first and secondsecondary windings are stamped and formed sheets of metal.

Turning now to FIGS. 21 to 23, illustrated are views of an embodiment ofa magnetic device. FIGS. 21 and 22 illustrate a schematic view and aside view, respectively, of the magnetic device having a primary windingand center-tapped secondary windings around a magnetic core. FIG. 23illustrates a partially assembled perspective view of the magneticdevice. The magnetic core of the magnetic device includes a first L-coresegment LC1 and an opposing second L-core segment LC2. The first L-coresegment LC1 includes a first leg LEG1 and a second leg LEG2 extendingtherefrom. The second L-core segment LC2 includes a first leg LEG1 and asecond leg LEG2 extending therefrom. The first and second L-coresegments LC1, LC2 may be designed with the flexibility as describedabove with respect to FIGS. 11 and 12.

The magnetic device includes a primary winding PR with first and secondprimary terminals p₁, p₂ for connection to another circuit element of apower converter or the like. The primary winding PR is formed around(e.g., wound around) the first leg LEG1 of the second L-core segmentLC2. The magnetic device includes center-tapped secondary windings witha first secondary winding SC1 and a second secondary winding SC2 withfirst, second and third secondary terminals s₁, s₂, s₃ for connection toanother circuit element of a power converter or the like. The center tapof the center-tapped secondary windings is coupled to the thirdsecondary terminal s₃. The first and second secondary windings SC1, SC2are formed around (e.g., stamped and formed sheet of metal placedaround) the first leg LEG1 of the second L-core segment LC2. The firstand second secondary windings SC1, SC2 are formed over the primarywinding PR around the first leg LEG1 of the second L-core segment LC2.

The primary winding PR may be dielectrically isolated from the secondarywindings SC1, SC2 by an insulating layer (e.g., tape or bobbin, notshown). Additionally, the primary winding PR and/or the secondarywindings SC1, SC2 may be dielectrically isolated from the second L-coresegment LC2 by an insulating layer (e.g., tape or bobbin, not shown).The magnetic device may also be encapsulated by a protective pottingmaterial such as epoxy individually or in combination with other circuitelements as part of a power converter or the like.

Turning now to FIGS. 24 to 27, illustrated are views of an embodiment ofa magnetic device. FIGS. 24 and 25 illustrate a schematic view and aside view, respectively, of the magnetic device having primary windingscoupled in series and center-tapped secondary windings around a magneticcore. FIGS. 26 and 27 illustrate partially assembled perspective viewsof the magnetic device. The magnetic core of the magnetic deviceincludes a first L-core segment LC1 and an opposing second L-coresegment LC2. The first L-core segment LC1 includes a first leg LEG1 anda second leg LEG2 extending therefrom. The second L-core segment LC2includes a first leg LEG1 and a second leg LEG2 extending therefrom. Thefirst and second L-core segments LC1, LC2 may be designed with theflexibility as described above with respect to FIGS. 11 and 12.

The magnetic device includes a first primary winding PR1 coupled inseries with a second primary winding PR2 with first, second and thirdprimary terminals p₁, p₂, p₃ for connection to another circuit elementof a power converter or the like. An end of the first and second primarywindings PR1, PR2 are coupled together at the third primary terminal p₃.The first primary winding PR1 is formed around (e.g., wound around) thefirst leg LEG1 of the first L-core segment LC1 and the second primarywinding PR2 is formed around (e.g., wound around) the first leg LEG1 ofthe second L-core segment LC2.

The magnetic device includes center-tapped secondary windings with afirst secondary winding SC1 and a second secondary winding SC2 withfirst, second and third secondary terminals s₁, s₂, s₃ for connection toanother circuit element of a power converter or the like. The center tapof the center-tapped secondary windings is coupled to the thirdsecondary terminal s₃. The first secondary winding SC1 is formed around(e.g., stamped and formed sheet of metal placed around) the first legLEG1 of the first L-core segment LC1 and the second secondary windingSC2 is formed around (e.g., stamped and formed sheet of metal placedaround) the first leg LEG1 of the second L-core segment LC2. The firstsecondary winding SC1 is formed over the first primary winding PR1around the first leg LEG1 of the first L-core segment LC1, and thesecond secondary winding SC2 is formed over the second primary windingPR2 around the first leg LEG1 of the second L-core segment LC2.

The primary windings PR1, PR2 may be dielectrically isolated fromrespective secondary windings SC1, SC2 by an insulating layer (e.g.,tape or bobbin, not shown). Additionally, the primary windings PR1, PR2and/or the secondary windings SC1, SC2 may be dielectrically isolatedfrom the respective first and second L-core segments LC1, LC2 by aninsulating layer (e.g., tape or bobbin, not shown). The magnetic devicemay also be encapsulated by a protective potting material such as epoxyindividually or in combination with other circuit elements as part of apower converter or the like.

Turning now to FIGS. 28 to 31, illustrated are views of an embodiment ofa magnetic device. FIGS. 28 and 29 illustrate a schematic view and aside view, respectively, of the magnetic device having primary windingscoupled in parallel and center-tapped secondary windings around amagnetic core. FIGS. 30 and 31 illustrate partially assembledperspective views of the magnetic device. The magnetic core of themagnetic device includes a first L-core segment LC1 and an opposingsecond L-core segment LC2. The first L-core segment LC1 includes a firstleg LEG1 and a second leg LEG2 extending therefrom. The second L-coresegment LC2 includes a first leg LEG1 and a second leg LEG2 extendingtherefrom. The first and second L-core segments LC1, LC2 may be designedwith the flexibility as described above with respect to FIGS. 11 and 12.

The magnetic device includes a first primary winding PR1 coupled inparallel with a second primary winding PR2 with first and second andprimary terminals p₁, p₂ for connection to another circuit element of apower converter or the like. Ends of the first and second primarywindings PR1, PR2 are coupled together at the first and second primaryterminals p₁, p₂. The first primary winding PR1 is formed around (e.g.,wound around) the first leg LEG1 of the first L-core segment LC1 and thesecond primary winding PR2 is formed around (e.g., wound around) thefirst leg LEG1 of the second L-core segment LC2.

The magnetic device includes center-tapped secondary windings with afirst secondary winding SC1 and a second secondary winding SC2 withfirst, second and third secondary terminals s₁, s₂, s₃ for connection toanother circuit element of a power converter or the like. The center tapof the center-tapped secondary windings is coupled to the thirdsecondary terminal s₃. The first secondary winding SC1 is formed around(e.g., stamped and formed sheet of metal placed around) the first legLEG1 of the first L-core segment LC1 and the second secondary windingSC2 is formed around (e.g., stamped and formed sheet of metal placedaround) the first leg LEG1 of the second L-core segment LC2. The firstsecondary winding SC1 is formed over the first primary winding PR1around the first leg LEG1 of the first L-core segment LC1, and thesecond secondary winding SC2 is formed over the second primary windingPR2 around the first leg LEG1 of the second L-core segment LC2.

The primary windings PR1, PR2 may be dielectrically isolated fromrespective secondary windings SC1, SC2 by an insulating layer (e.g.,tape or bobbin, not shown). Additionally, the primary windings PR1, PR2and/or the secondary windings SC1, SC2 may be dielectrically isolatedfrom the respective first and second L-core segments LC1, LC2 by aninsulating layer (e.g., tape or bobbin, not shown). The magnetic devicemay also be encapsulated by a protective potting material such as epoxyindividually or in combination with other circuit elements as part of apower converter or the like.

Thus, a magnetic device, a method of forming the same and a powerconverter have been introduced herein. In one embodiment, the magneticdevice includes a first L-core segment including a first leg and asecond leg extending therefrom. The magnetic device also includes anopposing second L-core segment including a first leg and a second legextending therefrom. The magnetic device further includes acenter-tapped secondary winding with a first secondary winding and asecond secondary winding formed around at least one of the first leg andthe second leg of the first L-core segment or the second L-core segment.In one embodiment, the second leg of the first L-core segment issubstantially perpendicular to the first leg of the first L-core segmentand the second leg of the second L-core segment is substantiallyperpendicular to the first leg of the second L-core segment.Additionally, a length of the first leg of the first L-core segment iselongated with respect to a length of the second leg of the first L-coresegment and a length of the first leg of the second L-core segment iselongated with respect to a length of the second leg of the secondL-core segment. Additionally, a thickness of the first leg and thesecond leg of the first L-core segment is substantially equal and athickness of the first leg and the second leg of the second L-coresegment is substantially equal.

In one embodiment, the first and second secondary windings are formedaround the first leg of the second L-core segment. The magnetic devicemay also include a primary winding formed around at least one of thefirst leg and the second leg of the first L-core segment or the secondL-core segment. In a related embodiment, the magnetic device may includea primary winding formed around the first leg of the second L-coresegment, and the first and second secondary windings are formed over theprimary winding around the first leg of the second L-core segment. Thefirst and second secondary windings are stamped and formed sheets ofmetal. In another embodiment, the magnetic device includes a firstprimary winding formed around the first leg of the first L-core segmentand a second primary winding formed around the first leg of the secondL-core segment. In accordance therewith, the first secondary winding isformed over the first primary winding around the first leg of the firstL-core segment and the second secondary winding is formed over thesecond primary winding around the first leg of the second L-coresegment.

Turning now to FIGS. 32 to 35, illustrated are views of an embodiment ofa magnetic device. FIGS. 32 and 33 illustrate a schematic view and aside view, respectively, of a magnetic device formed as an E-coremagnetic device having primary windings coupled in series and secondarywindings coupled in parallel around a magnetic core. FIGS. 34 and 35illustrate partially assembled perspective views of the E-core magneticdevice. The magnetic core of the E-core magnetic device includes a firstcore section including a first L-core segment LC11 and an opposingsecond L-core segment LC12. The first L-core segment LC11 includes afirst leg LEG1 and a second leg LEG2 extending therefrom. The secondL-core segment LC12 includes a first leg LEG1 and a second leg LEG2extending therefrom. The magnetic core of the E-core magnetic deviceincludes a second core section including a first L-core segment LC21 andan opposing second L-core segment LC22. The first L-core segment LC21includes a first leg LEG1 and a second leg LEG2 extending therefrom. Thesecond L-core segment LC22 includes a first leg LEG1 and a second legLEG2 extending therefrom. In the illustrated embodiment, exteriorsurfaces EXS of the second leg LEG2 of the second L-core segments LC12,LC22 of the first and second core sections, respectively, are matedtogether (e.g., glued, adhesively secured or banded together). Also, endsurfaces ES of the first leg LEG1 of the first L-core segments LC11,LC21 of the first and second core sections, respectively, are matedtogether (e.g., glued, adhesively secured or banded together). The firstand second L-core segments LC11, LC12, LC21, LC22 may be designed withthe flexibility as described above with respect to FIGS. 11 and 12.

The magnetic device includes a first primary winding PR1 coupled inseries with a second primary winding PR2 with first, second and thirdprimary terminals p₁, p₂, p₃ for connection to another circuit elementof a power converter or the like. An end of the first and second primarywindings PR1, PR2 are coupled together at the third primary terminal p₃.The first primary winding PR1 is formed around (e.g., wound around) thefirst leg LEG1 of the second L-core segment LC12 of the first coresection and the second primary winding PR2 is formed around (e.g., woundaround) the first leg LEG1 of the second L-core segment LC22 of thesecond core section.

The magnetic device includes a first secondary winding SC1 coupled inparallel with a second secondary winding SC2 with first and secondsecondary terminals s₁, s₂ for connection to another circuit element ofa power converter or the like. An end of the first and second secondarywindings SC1, SC2 are coupled together. The first secondary winding SC1is formed around (e.g., stamped and formed sheet of metal placed around)the first leg LEG1 of the second L-core segment LC12 of the first coresection and the second secondary winding SC2 is formed around (e.g.,stamped and formed sheet of metal placed around) the first leg LEG1 ofthe second L-core segment LC22 of the second core section. The firstsecondary winding SC1 is formed over the first primary winding PR1around the first leg LEG1 of the second L-core segment LC12 of the firstcore section, and the second secondary winding SC2 is formed over thesecond primary winding PR2 around the first leg LEG1 of the secondL-core segment LC22 of the second core section.

The primary windings PR1, PR2 may be dielectrically isolated fromrespective secondary windings SC1, SC2 by an insulating layer (e.g.,tape or bobbin, not shown). Additionally, the primary windings PR1, PR2and/or the secondary windings SC1, SC2 may be dielectrically isolatedfrom the respective second L-core segments LC12, LC22 by an insulatinglayer (e.g., tape or bobbin, not shown). The magnetic device may also beencapsulated by a protective potting material such as epoxy individuallyor in combination with other circuit elements as part of a powerconverter or the like.

Turning now to FIGS. 36 to 39, illustrated are views of an embodiment ofa magnetic device. FIGS. 36 and 37 illustrate a schematic view and aside view, respectively, of a magnetic device formed as an E-coremagnetic device having primary windings coupled in parallel andcenter-tapped secondary windings around a magnetic core. FIGS. 38 and 39illustrate partially assembled perspective views of the E-core magneticdevice. The magnetic core of the E-core magnetic device includes a firstcore section including a first L-core segment LC11 and an opposingsecond L-core segment LC12. The first L-core segment LC11 includes afirst leg LEG1 and a second leg LEG2 extending therefrom. The secondL-core segment LC12 includes a first leg LEG1 and a second leg LEG2extending therefrom. The magnetic core of the E-core magnetic deviceincludes a second core section including a first L-core segment LC21 andan opposing second L-core segment LC22. The first L-core segment LC21includes a first leg LEG1 and a second leg LEG2 extending therefrom. Thesecond L-core segment LC22 includes a first leg LEG1 and a second legLEG2 extending therefrom. In the illustrated embodiment, exteriorsurfaces EXS of the first leg LEG1 of the second L-core segments LC12,LC22 of the first and second core sections, respectively, are matedtogether (e.g., glued, adhesively secured or banded together). Also, endsurfaces ES of the second leg LEG2 of the first L-core segments LC11,LC21 of the first and second core sections, respectively, are matedtogether (e.g., glued, adhesively secured or banded together). The firstand second L-core segments LC11, LC12, LC21, LC22 may be designed withthe flexibility as described above with respect to FIGS. 11 and 12.

The magnetic device includes a first primary winding PR1 coupled inparallel with a second primary winding PR2 with first and second andprimary terminals p₁, p₂ for connection to another circuit element of apower converter or the like. Ends of the first and second primarywindings PR1, PR2 are coupled together at the first and second primaryterminals p₁, p₂. The first primary winding PR1 is formed around (e.g.,wound around) the first leg LEG1 of the first L-core segment LC11 of thefirst core section and the second primary winding PR2 is formed around(e.g., wound around) the first leg LEG1 of the first L-core segment LC21of the second core section.

The magnetic device includes center-tapped secondary windings with afirst secondary winding SC1 and a second secondary winding SC2 withfirst, second and third secondary terminals s₁, s₂, s₃ for connection toanother circuit element of a power converter or the like. The center tapof the center-tapped secondary windings is coupled to the thirdsecondary terminal s₃. The first secondary winding SC1 is formed around(e.g., stamped and formed sheet of metal placed around) the first legLEG1 of the first L-core segment LC11 of the first core section and thesecond secondary winding SC2 is formed around (e.g., stamped and formedsheet of metal placed around) the first leg LEG1 of the first L-coresegment LC21 of the second core section. The first secondary winding SC1is formed over the first primary winding PR1 around the first leg LEG1of the first L-core segment LC11 of the first core section, and thesecond secondary winding SC2 is formed over the second primary windingPR2 around the first leg LEG1 of the first L-core segment LC21 of thesecond core section.

The primary windings PR1, PR2 may be dielectrically isolated fromrespective secondary windings SC1, SC2 by an insulating layer (e.g.,tape or bobbin, not shown). Additionally, the primary windings PR1, PR2and/or the secondary windings SC1, SC2 may be dielectrically isolatedfrom the respective first L-core segments LC11, LC21 by an insulatinglayer (e.g., tape or bobbin, not shown). The magnetic device may also beencapsulated by a protective potting material such as epoxy individuallyor in combination with other circuit elements as part of a powerconverter or the like.

Thus, a magnetic device, a method of forming the same and a powerconverter have been introduced herein. In one embodiment, the magneticdevice includes a first core section having a first L-core segmentincluding a first leg and a second leg extending therefrom, and anopposing second L-core segment including a first leg and a second legextending therefrom. The magnetic device also includes a second coresection having a first L-core segment including a first leg and a secondleg extending therefrom, and an opposing second L-core segment includinga first leg and a second leg extending therefrom. A surface of thesecond core section is mated (e.g., adhesively secured) to a surface ofthe first core section. In one embodiment, the second leg of the firstL-core segment of the first core section is substantially perpendicularto the first leg of the first L-core segment of the first core section,and the second leg of the second L-core segment of the first coresection is substantially perpendicular to the first leg of the secondL-core segment of the first core section. Additionally, a length of thefirst leg of the first L-core segment of the first core section iselongated with respect to a length of the second leg of the first L-coresegment of the first core section, and a length of the first leg of thesecond L-core segment of the first core section is elongated withrespect to a length of the second leg of the second L-core segment ofthe first core section Additionally, a thickness of the first leg andthe second leg of the first L-core segment of the first core section issubstantially equal and a thickness of the first leg and the second legof the second L-core segment of the first core section is substantiallyequal.

In one embodiment, a winding is formed around at least one of the firstleg and the second leg of the first L-core segment or the second L-coresegment of the first core section, and a winding is formed around atleast one of the first leg and the second leg of the first L-coresegment or the second L-core segment of the second core section.Regarding the mating of the first and second core sections, an endsurface of the first leg of the first L-core segment of the first coresection is mated to an end surface of the first leg of the first L-coresegment of the second core section, and an exterior surface of thesecond leg of the second L-core segment of the first core section ismated to an exterior surface of the second leg of the second L-coresegment of the second core section. Alternatively, an end surface of thesecond leg of the first L-core segment of the first core section ismated to an end surface of the second leg of the first L-core segment ofthe second core section, and an exterior surface of the first leg of thesecond L-core segment of the first core section is mated to an exteriorsurface of the first leg of the second L-core segment of the second coresection.

In one embodiment, the magnetic device includes first and second primarywindings formed around the first leg of the second L-core segment of thefirst and second core sections, respectively, and first and secondsecondary windings are formed around the first leg of the second L-coresegment of the first and second core sections, respectively.Alternatively, the magnetic device includes first and second primarywindings formed around the first leg of the first L-core segment of thefirst and second core sections, respectively, and first and secondsecondary windings are formed around the first leg of the first L-coresegment of the first and second core sections, respectively.

Turning now to FIGS. 40 to 41, illustrated is a schematic view and aside view, respectively, of a magnetic device in the form of a coupledinductor. The magnetic core of the coupled inductor includes a firstcore section including a first L-core segment LC11 and an opposingsecond L-core segment LC12. The first L-core segment LC11 includes afirst leg LEG1 and a second leg LEG2 extending therefrom. The secondL-core segment LC12 includes a first leg LEG1 and a second leg LEG2extending therefrom. The magnetic core of the coupled inductor includesa second core section including a first L-core segment LC21 and anopposing second L-core segment LC22. The first L-core segment LC21includes a first leg LEG1 and a second leg LEG2 extending therefrom. Thesecond L-core segment LC22 includes a first leg LEG1 and a second legLEG2 extending therefrom. In the illustrated embodiment, exteriorsurfaces EXS of the second leg LEG2 of the second L-core segments LC12,LC22 of the first and second core sections, respectively, are matedtogether (e.g., glued, adhesively secured or banded together). Also, endsurfaces ES of the first leg LEG1 of the first L-core segments LC11,LC21 of the first and second core sections, respectively, are matedtogether (e.g., glued, adhesively secured or banded together). The firstand second L-core segments LC11, LC12, LC21, LC22 may be designed withthe flexibility as described above with respect to FIGS. 11 and 12.

The magnetic device includes center-tapped secondary windings with afirst secondary winding SC1 and a second secondary winding SC2 withfirst, second and third secondary terminals s₁, s₂, s₃ for connection toanother circuit element of a power converter or the like. The center tapof the center-tapped secondary windings is coupled to an inductorwinding IC and to the third secondary terminal s₃. The first secondarywinding SC1 is formed around (e.g., stamped and formed sheet of metalplaced around) the first leg LEG1 of the second L-core segment LC12 ofthe first core section and the second secondary winding SC2 is formedaround (e.g., stamped and formed sheet of metal placed around) the firstleg LEG1 of the second L-core segment LC22 of the second core section.The inductor winding IC is formed around the second leg LEG2 of thesecond L-core segments LC12, LC22 of the first core section and thesecond core section, respectively.

The secondary windings SC1, SC2 and/or the inductor winding IC may bedielectrically isolated from the respective second L-core segments LC12,LC22 by an insulating layer (e.g., tape or bobbin, not shown). Themagnetic device may also be encapsulated by a protective pottingmaterial such as epoxy individually or in combination with other circuitelements as part of a power converter or the like. It should be notedthat the coupled inductor including forming the secondary windings SC1,SC2 and/or the inductor winding IC about the first and second coresections may be assembled as described above.

Turning now to FIG. 42, illustrated is a side view of an embodiment of amagnetic core of a magnetic device in the form of a coupled inductor.The magnetic core of FIG. 42 is analogous to the magnetic core of FIG.41 with the addition of gaps therein. A first gap (designated “a”)supports energy storage and a second gap (designated “b”) substantiallyprevents circulating magnetic flux. The first gap “a” may be created bygrinding down the second leg LEG2 of the second L-core segments LC12,LC22 of the first and second core sections, respectively. The second gap“b” may be created by placing a spacer (partially shown and designated“s”) between the exterior surfaces EXS of the second leg LEG2 of thesecond L-core segments LC12, LC22 of the first and second core sections,respectively. The gaps “a”, “b” may be formed by, without limitation,air, a filler such as an epoxy or a spacer “s”. For ease ofillustration, the second gap “b” is shown as partially filled with airor other filler (an upper portion thereof) and partially filled with thespacer “s”. Thus, the magnetic device includes at least one gap betweena pair of adjacent legs therein. Of course, windings may be formedaround the magnetic core of the coupled inductor as illustrated above.

Turning now to FIGS. 43 to 44, illustrated is a schematic view and aside view, respectively, of a magnetic device in the form of a coupledinductor. The magnetic core of the coupled inductor includes a firstcore section including a first L-core segment LC11 and an opposingsecond L-core segment LC12. The first L-core segment LC11 includes afirst leg LEG1 and a second leg LEG2 extending therefrom. The secondL-core segment LC12 includes a first leg LEG1 and a second leg LEG2extending therefrom. The magnetic core of the coupled inductor includesa second core section including a first L-core segment LC21 and anopposing second L-core segment LC22. The first L-core segment LC21includes a first leg LEG1 and a second leg LEG2 extending therefrom. Thesecond L-core segment LC22 includes a first leg LEG1 and a second legLEG2 extending therefrom. In the illustrated embodiment, exteriorsurfaces EXS of the first leg LEG1 of the second L-core segments LC12,LC22 of the first and second core sections, respectively, are matedtogether (e.g., glued, adhesively secured or banded together). Also, endsurfaces ES of the second leg LEG2 of the first L-core segments LC11,LC21 of the first and second core sections, respectively, are matedtogether (e.g., glued, adhesively secured or banded together). The firstand second L-core segments LC11, LC12, LC21, LC22 may be designed withthe flexibility as described above with respect to FIGS. 11 and 12.

The magnetic device includes center-tapped secondary windings with afirst secondary winding SC1 and a second secondary winding SC2 withfirst, second and third secondary terminals s₁, s₂, s₃ for connection toanother circuit element of a power converter or the like. The center tapof the center-tapped secondary windings is coupled to an inductorwinding IC and to the third secondary terminal s₃. The first secondarywinding SC1 is formed around (e.g., stamped and formed sheet of metalplaced around) the first leg LEG1 of the first L-core segment LC11 ofthe first core section and the second secondary winding SC2 is formedaround (e.g., stamped and formed sheet of metal placed around) the firstleg LEG1 of the first L-core segment LC21 of the second core section.The inductor winding IC is formed around the first leg LEG1 of thesecond L-core segments LC12, LC22 of the first core section and thesecond core section, respectively.

The secondary windings SC1, SC2 and/or the inductor winding IC may bedielectrically isolated from the respective first L-core segments LC11,LC21 and/or second L-core segments LC12, LC22 by an insulating layer(e.g., tape or bobbin, not shown). The magnetic device may also beencapsulated by a protective potting material such as epoxy individuallyor in combination with other circuit elements as part of a powerconverter or the like. It should be noted that the coupled inductorincluding forming the secondary windings SC1, SC2 and/or the inductorwinding IC about the first and second core sections may be assembled asdescribed above.

Turning now to FIG. 45, illustrated is a side view of an embodiment of amagnetic core of a magnetic device in the form of a coupled inductor.The magnetic core of FIG. 45 is analogous to the magnetic core of FIG.44 with the addition of gaps therein. A first gap (designated “a”)supports energy storage and a second gap (designated “b”) substantiallyprevents circulating magnetic flux. The first gap “a” may be created bygrinding down the first leg LEG1 of the second L-core segments LC12,LC22 of the first and second core sections, respectively. The second gap“b” may be created by placing a spacer (partially shown and designated“s”) between the exterior surfaces EXS of the first leg LEG1 of thesecond L-core segments LC12, LC22 of the first and second core sections,respectively. The gaps “a”, “b” may be formed by, without limitation,air, a filler such as an epoxy or a spacer “s”. For ease ofillustration, the second gap “b” is shown as partially filled with airor other filler (an upper portion thereof) and partially filled with thespacer “s”. Thus, the magnetic device includes at least one gap betweena pair of adjacent legs therein. Of course, windings may be formedaround the magnetic core of the coupled inductor as illustrated above.

Thus, a magnetic device, a method of forming the same and a powerconverter have been introduced herein. In one embodiment, the magneticdevice includes a magnetic core including a first core section and asecond core section. The first core section includes a first L-coresegment with a first leg and a second leg extending therefrom, and anopposing second L-core segment with a first leg and a second legextending therefrom. The second core section includes a first L-coresegment with a first leg and a second leg extending therefrom, and anopposing second L-core segment with a first leg and a second legextending therefrom. A surface of the second core section is mated(e.g., adhesively secured) to a surface of the first core section. Themagnetic device also includes a center-tapped secondary winding with afirst secondary winding and a second secondary winding formed around atleast one of the first leg and the second leg of the first L-coresegment or the second L-core segment of the first core section or thesecond core section. The magnetic device also includes an inductorwinding formed around at least one of the first leg and the second legof the first L-core segment or the second L-core segment of the firstcore section or the second core section. The inductor winding is coupledto a center tap between the first secondary winding and the secondsecondary winding.

In one embodiment, the second leg of the first L-core segment of thefirst core section is substantially perpendicular to the first leg ofthe first L-core segment of the first core section, and the second legof the second L-core segment of the first core section is substantiallyperpendicular to the first leg of the second L-core segment of the firstcore section. Also, a length of the first leg of the first L-coresegment of the first core section is elongated with respect to a lengthof the second leg of the first L-core segment of the first core section,and a length of the first leg of the second L-core segment of the firstcore section is elongated with respect to a length of the second leg ofthe second L-core segment of the first core section. Additionally, athickness of the first leg and the second leg of the first L-coresegment of the first core section is substantially equal and a thicknessof the first leg and the second leg of the second L-core segment of thefirst core section is substantially equal.

In one embodiment, the first secondary winding is formed around thefirst leg of the second L-core segment of the first core section, thesecond secondary winding is formed around the first leg of the secondL-core segment of the second core section and the inductor winding isformed around the second leg of the second L-core segments of the firstcore section and the second core section. Alternatively, the firstsecondary winding is formed around the first leg of the first L-coresegment of the first core section, the second secondary winding isformed around the first leg of the first L-core segment of the secondcore section and the inductor winding is formed around the first leg ofthe second L-core segments of the first core section and the second coresection.

In one embodiment, an end surface of the first leg of the first L-coresegment of the first core section is mated to an end surface of thefirst leg of the first L-core segment of the second core section, and anexterior surface of the second leg of the second L-core segment of thefirst core section is mated to an exterior surface of the second leg ofthe second L-core segment of the second core section. Alternatively, anend surface of the second leg of the first L-core segment of the firstcore section is mated to an end surface of the second leg of the firstL-core segment of the second core section, and an exterior surface ofthe first leg of the second L-core segment of the first core section ismated to an exterior surface of the first leg of the second L-coresegment of the second core section. Also, the magnetic device mayinclude a gap between a pair of adjacent legs therein.

Turning now to FIGS. 46 to 47, illustrated is a schematic view and aside view, respectively, of a magnetic device in the form of anintegrated magnetic device. The magnetic core of the integrated magneticdevice includes a first core section including a first L-core segmentLC11 and an opposing second L-core segment LC12. The first L-coresegment LC11 includes a first leg LEG1 and a second leg LEG2 extendingtherefrom. The second L-core segment LC12 includes a first leg LEG1 anda second leg LEG2 extending therefrom. The magnetic core of theintegrated magnetic device includes a second core section including afirst L-core segment LC21 and an opposing second L-core segment LC22.The first L-core segment LC21 includes a first leg LEG1 and a second legLEG2 extending therefrom. The second L-core segment LC22 includes afirst leg LEG1 and a second leg LEG2 extending therefrom. In theillustrated embodiment, exterior surfaces EXS of the second leg LEG2 ofthe second L-core segments LC12, LC22 of the first and second coresections, respectively, are mated together (e.g., glued, adhesivelysecured or banded together). Also, end surfaces ES of the first leg LEG1of the first L-core segments LC11, LC21 of the first and second coresections, respectively, are mated together (e.g., glued, adhesivelysecured or banded together). The first and second L-core segments LC11,LC12, LC21, LC22 may be designed with the flexibility as described abovewith respect to FIGS. 11 and 12.

The magnetic device includes a first primary winding PR1 coupled inseries with a second primary winding PR2 with first, second and thirdprimary terminals p₁, p₂, p₃ for connection to another circuit elementof a power converter or the like. An end of the first and second primarywindings PR1, PR2 are coupled together at the third primary terminal p₃.The first primary winding PR1 is formed around (e.g., wound around) thefirst leg LEG1 of the second L-core segment LC12 of the first coresection and the second primary winding PR2 is formed around (e.g., woundaround) the first leg LEG1 of the second L-core segment LC22 of thesecond core section.

The magnetic device includes center-tapped secondary windings with afirst secondary winding SC1 and a second secondary winding SC2 withfirst, second and third secondary terminals s₁, s₂, s₃ for connection toanother circuit element of a power converter or the like. The center tapof the center-tapped secondary windings is coupled to an inductorwinding IC and to the third secondary terminal s₃. The first secondarywinding SC1 is formed around (e.g., stamped and formed sheet of metalplaced around) the first leg LEG1 of the second L-core segment LC12 ofthe first core section and the second secondary winding SC2 is formedaround (e.g., stamped and formed sheet of metal placed around) the firstleg LEG1 of the second L-core segment LC22 of the second core section.The inductor winding IC is formed around the second leg LEG2 of thesecond L-core segments LC12, LC22 of the first core section and thesecond core section, respectively.

The primary windings PR1, PR2 may be dielectrically isolated fromrespective secondary windings SC1, SC2 or the inductor winding IC by aninsulating layer (e.g., tape or bobbin, not shown). Additionally, theprimary windings PR1, PR2, and/or the secondary windings SC1, SC2 and/orthe inductor winding IC may be dielectrically isolated from therespective second L-core segments LC12, LC22 by an insulating layer(e.g., tape or bobbin, not shown). The magnetic device may also beencapsulated by a protective potting material such as epoxy individuallyor in combination with other circuit elements as part of a powerconverter or the like. It should be noted that the integrated magneticdevice including forming the primary windings PR1, PR2, the secondarywindings SC1, SC2 and/or the inductor winding IC about the first andsecond core sections may be assembled as described above.

Turning now to FIGS. 48 to 49, illustrated is a schematic view and aside view, respectively, of a magnetic device in the form of anintegrated magnetic device. The magnetic core of the integrated magneticdevice includes a first core section including a first L-core segmentLC11 and an opposing second L-core segment LC12. The first L-coresegment LC11 includes a first leg LEG1 and a second leg LEG2 extendingtherefrom. The second L-core segment LC12 includes a first leg LEG1 anda second leg LEG2 extending therefrom. The magnetic core of theintegrated magnetic device includes a second core section including afirst L-core segment LC21 and an opposing second L-core segment LC22.The first L-core segment LC21 includes a first leg LEG1 and a second legLEG2 extending therefrom. The second L-core segment LC22 includes afirst leg LEG1 and a second leg LEG2 extending therefrom. In theillustrated embodiment, exterior surfaces EXS of the first leg LEG1 ofthe second L-core segments LC12, LC22 of the first and second coresections, respectively, are mated together (e.g., glued, adhesivelysecured or banded together). Also, end surfaces ES of the second legLEG2 of the first L-core segments LC11, LC21 of the first and secondcore sections, respectively, are mated together (e.g., glued, adhesivelysecured or banded together). The first and second L-core segments LC11,LC12, LC21, LC22 may be designed with the flexibility as described abovewith respect to FIGS. 11 and 12.

The magnetic device includes a first primary winding PR1 coupled inseries with a second primary winding PR2 with first, second and thirdprimary terminals p₁, p₂, p₃ for connection to another circuit elementof a power converter or the like. An end of the first and second primarywindings PR1, PR2 are coupled together at the third primary terminal p₃.The first primary winding PR1 is formed around (e.g., wound around) thefirst leg LEG1 of the first L-core segment LC11 of the first coresection and the second primary winding PR2 is formed around (e.g., woundaround) the first leg LEG1 of the first L-core segment LC21 of thesecond core section.

The magnetic device includes center-tapped secondary windings with afirst secondary winding SC1 and a second secondary winding SC2 withfirst, second and third secondary terminals s₁, s₂, s₃ for connection toanother circuit element of a power converter or the like. The center tapof the center-tapped secondary windings is coupled to an inductorwinding IC and to the third secondary terminal s₃. The first secondarywinding SC1 is formed around (e.g., stamped and formed sheet of metalplaced around) the first leg LEG1 of the first L-core segment LC11 ofthe first core section and the second secondary winding SC2 is formedaround (e.g., stamped and formed sheet of metal placed around) the firstleg LEG1 of the first L-core segment LC21 of the second core section.The inductor winding IC is formed around the first leg LEG1 of thesecond L-core segments LC12, LC22 of the first core section and thesecond core section, respectively.

The primary windings PR1, PR2 may be dielectrically isolated fromrespective secondary windings SC1, SC2 or the inductor winding IC by aninsulating layer (e.g., tape or bobbin, not shown). Additionally, theprimary windings PR1, PR2, and/or the secondary windings SC1, SC2 and/orthe inductor winding IC may be dielectrically isolated from therespective first L-core segments LC11, LC21 and/or second L-coresegments LC12, LC22 by an insulating layer (e.g., tape or bobbin, notshown). The magnetic device may also be encapsulated by a protectivepotting material such as epoxy individually or in combination with othercircuit elements as part of a power converter or the like. It should benoted that the integrated magnetic device including forming the primarywindings PR1, PR2, the secondary windings SC1, SC2 and/or the inductorwinding IC about the first and second core sections may be assembled asdescribed above.

Thus, a magnetic device, a method of forming the same and a powerconverter have been introduced herein. In one embodiment, the magneticdevice includes a magnetic core including a first core section and asecond core section. The first core section includes a first L-coresegment with a first leg and a second leg extending therefrom, and anopposing second L-core segment with a first leg and a second legextending therefrom. The second core section includes a first L-coresegment with a first leg and a second leg extending therefrom, and anopposing second L-core segment with a first leg and a second legextending therefrom. A surface of the second core section is mated(e.g., adhesively secured) to a surface of the first core section. Themagnetic device includes a first primary winding and a second primarywinding formed around at least one of the first leg and the second legof the first L-core segment or the second L-core segment of the firstcore section or the second core section. The magnetic device alsoincludes a center-tapped secondary winding with a first secondarywinding and a second secondary winding formed around at least one of thefirst leg and the second leg of the first L-core segment or the secondL-core segment of the first core section or the second core section. Themagnetic device also includes an inductor winding formed around at leastone of the first leg and the second leg of the first L-core segment orthe second L-core segment of the first core section or the second coresection. The inductor winding is coupled to a center tap between thefirst secondary winding and the second secondary winding.

In one embodiment, the second leg of the first L-core segment of thefirst core section is substantially perpendicular to the first leg ofthe first L-core segment of the first core section, and the second legof the second L-core segment of the first core section is substantiallyperpendicular to the first leg of the second L-core segment of the firstcore section. Also, a length of the first leg of the first L-coresegment of the first core section is elongated with respect to a lengthof the second leg of the first L-core segment of the first core section,and a length of the first leg of the second L-core segment of the firstcore section is elongated with respect to a length of the second leg ofthe second L-core segment of the first core section. Additionally, athickness of the first leg and the second leg of the first L-coresegment of the first core section is substantially equal and a thicknessof the first leg and the second leg of the second L-core segment of thefirst core section is substantially equal.

In one embodiment, the first primary and secondary windings are formedaround the first leg of the second L-core segment of the first coresection, the second primary and secondary windings are formed around thefirst leg of the second L-core segment of the second core section, andthe inductor winding is formed around the second leg of the secondL-core segments of the first core section and the second core section.Alternatively, the first primary and secondary windings are formedaround the first leg of the first L-core segment of the first coresection, the second primary and secondary windings are formed around thefirst leg of the first L-core segment of the second core section, andthe inductor winding is formed around the first leg of the second L-coresegments of the first core section and the second core section. Thefirst and second secondary windings may be stamped and formed sheets ofmetal.

In one embodiment, an end surface of the first leg of the first L-coresegment of the first core section is mated to an end surface of thefirst leg of the first L-core segment of the second core section, and anexterior surface of the second leg of the second L-core segment of thefirst core section is mated to an exterior surface of the second leg ofthe second L-core segment of the second core section. Alternatively, anend surface of the second leg of the first L-core segment of the firstcore section is mated to an end surface of the second leg of the firstL-core segment of the second core section, and an exterior surface ofthe first leg of the second L-core segment of the first core section ismated to an exterior surface of the first leg of the second L-coresegment of the second core section.

The controller or related method as described above with respect to thepower converters may be implemented as hardware (embodied in one or morechips including an integrated circuit such as an application specificintegrated circuit), or may be implemented as software or firmware forexecution by a processor (e.g., a digital signal processor) inaccordance with memory. In particular, in the case of firmware orsoftware, the exemplary embodiment can be provided as a computer programproduct including a computer readable medium embodying computer programcode (i.e., software or firmware) thereon for execution by theprocessor.

Program or code segments making up the various embodiments may be storedin the computer readable medium. For instance, a computer programproduct including a program code stored in a computer readable medium(e.g., a non-transitory computer readable medium) may form variousembodiments. The “computer readable medium” may include any medium thatcan store or transfer information. Examples of the computer readablemedium include an electronic circuit, a semiconductor memory device, aread only memory (“ROM”), a flash memory, an erasable ROM (“EROM”), afloppy diskette, a compact disk (“CD”)-ROM, and the like.

Those skilled in the art should understand that the previously describedembodiments of a power converter including an L-core segment and relatedmethods of forming the same are submitted for illustrative purposesonly. While a magnetic device has been described in the environment of apower converter, the magnetic device may also be applied to othersystems such as, without limitation, a power amplifier and a motorcontroller.

For a better understanding of power converters, see “Modern DC-to-DCPower Switch-mode Power Converter Circuits,” by Rudolph P. Severns andGordon Bloom, Van Nostrand Reinhold Company, New York, N.Y. (1985) and“Principles of Power Electronics,” by J. G. Kassakian, M. F. Schlechtand G. C. Verghese, Addison-Wesley (1991). The aforementioned referencesare incorporated herein by reference in their entirety.

Also, although the present invention and its advantages have beendescribed in detail, it should be understood that various changes,substitutions and alterations can be made herein without departing fromthe spirit and scope of the invention as defined by the appended claims.For example, many of the processes discussed above can be implemented indifferent methodologies and replaced by other processes, or acombination thereof.

Moreover, the scope of the present application is not intended to belimited to the particular embodiments of the process, machine,manufacture, composition of matter, means, methods, and steps describedin the specification. As one of ordinary skill in the art will readilyappreciate from the disclosure of the present invention, processes,machines, manufacture, compositions of matter, means, methods, or steps,presently existing or later to be developed, that perform substantiallythe same function or achieve substantially the same result as thecorresponding embodiments described herein may be utilized according tothe present invention. Accordingly, the appended claims are intended toinclude within their scope such processes, machines, manufacture,compositions of matter, means, methods, or steps.

What is claimed is:
 1. A magnetic device, comprising: a magnetic core,comprising: a first core section, comprising: a single-piece, firstL-core segment including a first leg and a second leg extendingtherefrom, and an opposing, single-piece, second L-core segmentincluding a first leg and a second leg extending therefrom; and a secondcore section, comprising: a single-piece, first L-core segment includinga first leg and a second leg extending therefrom, and an opposing,single-piece, second L-core segment including a first leg and a secondleg extending therefrom, a surface of said second core section beingmated to a surface of said first core section; a first primary windingand a second primary winding formed around at least one of said firstleg and said second leg of said first L-core segment or said secondL-core segment of said first core section or said second core section; acenter-tapped secondary winding with a first secondary winding and asecond secondary winding formed around at least one of said first legand said second leg of said first L-core segment or said second L-coresegment of said first core section or said second core section, saidfirst primary winding and said first secondary winding being formedaround a common leg; and an inductor winding formed around at least oneof said first leg and said second leg of said first L-core segment orsaid second L-core segment of said first core section or said secondcore section.
 2. The magnetic device as recited in claim 1 wherein saidsecond leg of said first L-core segment of said first core section issubstantially perpendicular to said first leg of said first L-coresegment of said first core section, and said second leg of said secondL-core segment of said first core section is substantially perpendicularto said first leg of said second L-core segment of said first coresection.
 3. The magnetic device as recited in claim 1 wherein a lengthof said first leg of said first L-core segment of said first coresection is elongated with respect to a length of said second leg of saidfirst L-core segment of said first core section, and a length of saidfirst leg of said second L-core segment of said first core section iselongated with respect to a length of said second leg of said secondL-core segment of said first core section.
 4. The magnetic device asrecited in claim 1 wherein a thickness of said first leg and said secondleg of said first L-core segment of said first core section issubstantially equal and a thickness of said first leg and said secondleg of said second L-core segment of said first core section issubstantially equal.
 5. The magnetic device as recited in claim 1wherein said inductor winding is coupled to a center tap between saidfirst secondary winding and said second secondary winding.
 6. Themagnetic device as recited in claim 1 wherein said first primary windingand said first secondary winding are formed around said first leg ofsaid second L-core segment of said first core section, said secondprimary winding and said second secondary winding are formed around saidfirst leg of said second L-core segment of the second core section, andsaid inductor winding is formed around said second leg of said secondL-core segments of said first core section and said second core section.7. The magnetic device as recited in claim 1 wherein said first primarywinding and said first secondary winding are formed around said firstleg of said first L-core segment of said first core section, said secondprimary winding and said second secondary winding are formed around saidfirst leg of said first L-core segment of said second core section, andsaid inductor winding is formed around said first leg of said secondL-core segments of said first core section and said second core section.8. The magnetic device as recited in claim 1 wherein an end surface ofsaid first leg of said first L-core segment of said first core sectionis mated to an end surface of said first leg of said first L-coresegment of said second core section, and an exterior surface of saidsecond leg of said second L-core segment of said first core section ismated to an exterior surface of said second leg of said second L-coresegment of said second core section.
 9. The magnetic device as recitedin claim 1 wherein an end surface of said second leg of said firstL-core segment of said first core section is mated to an end surface ofsaid second leg of said first L-core segment of said second coresection, and an exterior surface of said first leg of said second L-coresegment of said first core section is mated to an exterior surface ofsaid first leg of said second L-core segment of said second coresection.
 10. The magnetic device as recited in claim 1 wherein first andsecond secondary windings are stamped and formed sheets of metal.
 11. Apower converter, comprising: a main switch coupled to an input of saidpower converter; a magnetic device coupled to said main switch,comprising: a magnetic core, comprising: a first core section,comprising: a single-piece, first L-core segment including a first legand a second leg extending therefrom, and an opposing, single-piece,second L-core segment including a first leg and a second leg extendingtherefrom; and a second core section, comprising: a single-piece, firstL-core segment including a first leg and a second leg extendingtherefrom, and an opposing, single-piece, second L-core segmentincluding a first leg and a second leg extending therefrom, a surface ofsaid second core section being mated to a surface of said first coresection; a first primary winding and a second primary winding formedaround at least one of said first leg and said second leg of said firstL-core segment or said second L-core segment of said first core sectionor said second core section; a center-tapped secondary winding with afirst secondary winding and a second secondary winding formed around atleast one of said first leg and said second leg of said first L-coresegment or said second L-core segment of said first core section or saidsecond core section, said first primary winding and said first secondarywinding being formed around a common leg; and an inductor winding formedaround at least one of said first leg and said second leg of said firstL-core segment or said second L-core segment of said first core sectionor said second core section; an auxiliary switch coupled to saidmagnetic device; and an output filter capacitor coupled to saidauxiliary switch and an output of said power converter.
 12. The powerconverter as recited in claim 11 wherein said second leg of said firstL-core segment of said first core section is substantially perpendicularto said first leg of said first L-core segment of said first coresection, and said second leg of said second L-core segment of said firstcore section is substantially perpendicular to said first leg of saidsecond L-core segment of said first core section.
 13. The powerconverter as recited in claim 11 wherein a length of said first leg ofsaid first L-core segment of said first core section is elongated withrespect to a length of said second leg of said first L-core segment ofsaid first core section, and a length of said first leg of said secondL-core segment of said first core section is elongated with respect to alength of said second leg of said second L-core segment of said firstcore section.
 14. The power converter as recited in claim 11 wherein athickness of said first leg and said second leg of said first L-coresegment of said first core section is substantially equal and athickness of said first leg and said second leg of said second L-coresegment of said first core section is substantially equal.
 15. The powerconverter as recited in claim 11 wherein said inductor winding iscoupled to a center tap between said first secondary winding and saidsecond secondary winding.
 16. The power converter as recited in claim 11wherein said first primary winding and said first secondary winding areformed around said first leg of said second L-core segment of said firstcore section, said second primary winding and said second secondarywinding are formed around said first leg of said second L-core segmentof the second core section, and said inductor winding is formed aroundsaid second leg of said second L-core segments of said first coresection and said second core section.
 17. The power converter as recitedin claim 11 wherein said first primary winding and said first secondarywinding are formed around said first leg of said first L-core segment ofsaid first core section, said second primary winding and said secondsecondary winding are formed around said first leg of said first L-coresegment of said second core section, and said inductor winding is formedaround said first leg of said second L-core segments of said first coresection and said second core section.
 18. The power converter as recitedin claim 11 wherein an end surface of said first leg of said firstL-core segment of said first core section is mated to an end surface ofsaid first leg of said first L-core segment of said second core section,and an exterior surface of said second leg of said second L-core segmentof said first core section is mated to an exterior surface of saidsecond leg of said second L-core segment of said second core section.19. The power converter as recited in claim 11 wherein an end surface ofsaid second leg of said first L-core segment of said first core sectionis mated to an end surface of said second leg of said first L-coresegment of said second core section, and an exterior surface of saidfirst leg of said second L-core segment of said first core section ismated to an exterior surface of said first leg of said second L-coresegment of said second core section.
 20. The power converter as recitedin claim 11 wherein said first and second secondary windings are stampedand formed sheets of metal.